An antenna is a transducer designed to transmit and/or receive radio, television, microwave, telephone, and/or radar signals, i.e., an antenna converts electrical currents of a particular frequency into electromagnetic waves and, vice versa. Physically, an antenna is an arrangement of one or more electrical conductors that is arranged to generate a radiating electromagnetic field in response to an applied alternating voltage and the associated alternating electric current, or that can be placed in an electromagnetic field so that the field will induce an alternating current in the antenna and a voltage between its terminals.
Portable wireless communication electronic devices, such as mobile phones, typically include an antenna that is connected to electrically conducting tracks or contacts on a printed wiring board using techniques such as soldering or welding. Manufacturers of such electronic devices are under constant pressure to reduce the physical size, weight, and cost of the devices and improve their electrical performance. Low cost requirements dictate that the electronic device and its antenna should be incomplex and inexpensive to manufacture, produce and/or assemble.
In recent years, a new type of antenna has evolved that is small and has a high radiation efficiency, and is therefore of interest for use in cellular phones. In a dielectric resonator antenna (DRA), a probe can excite a transmission mode in a resonating dielectric antenna volume.
Within the framework of the development of antennas associated with mass-market products and use in domestic wireless networks, antennas consisting of a dielectric resonator have been identified as an interesting and viable commercial solution. Specifically, antennas of this type exhibit good properties in terms of passband and radiation. Moreover, they readily take the form of discrete components that can be surface mounted. Components of this type are known by the term, SMC components. SMC components are of interest, in the field of wireless communications for the mass-market, since they allow the use of low-cost substrates, thereby leading to a reduction in costs while ensuring equipment integration. Moreover, when RF frequency functions are developed in the form of SMC components, good performance is obtained despite the low quality of the substrate and integration is often favored thereby.
Moreover, new requirements, in terms of throughput, are leading to the use of high-throughput cellular communication networks such as 0G, 1G, 2G, 3G, and 4G or multimedia networks such as Hyperlan2 and IEEE 802.11A networks. In this case, the antenna must be able to ensure operation over a wide frequency band. Currently, DRA consist of a dielectric patch of any shape, characterized by its relative permittivity. The passband is directly related to the dielectric constant which therefore conditions the size of the resonator. Thus, the lower the permittivity, the more wideband the DRA antenna, but in this case, the component is bulky. However, in the case of use in wireless communication networks, the compactness constraints demand a reduction in the size of dielectric resonator antennas, possibly leading to incompatibility with the bandwidths required for such applications.
A trend to enhance the wireless data rate, in which compact and channel uncorrelated antenna is vital for such systems, is MIMO (multi-input, multi-output) antenna system.
U.S. Patent Application Publication No. 2008/0122703, by the same inventor, incorporated in its entirety herein by reference, relates to a dielectric radiator antenna arrangement for a communication device having a ground plane. The antenna arrangement may include a dielectric volume having a central axis normal to the ground plane, and mode-exciting elements. The mode-exciting elements may include a first mode-exciting element provided in or attached to the dielectric volume and extending in a plane provided at a first distance from the central axis perpendicular to the ground plane, and a second mode-exciting element provided in or attached to the dielectric volume and extending in a plane provided at a second distance from the central axis and perpendicular to both the ground plane and the plane of the first mode-exciting element. The antenna arrangement can be used for simultaneously transmitting and receiving more than one signal at one frequency with reduced coupling.